Alright, let's solve this problem step by step. We have 1128 and 5539 and we're adding them together.

Step 1: We'll start by adding the digits 8 & 9 in column 1 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 2 & 3 in column 2 and get 6.

Step 3: We'll start by adding the digits 1 & 5 in column 3 and get 6.

Step 4: We'll start by adding the digits 1 & 5 in column 4 and get 6.

So, 1128 + 5539 = 6667.

